Xcode 10

• Updates for Xcode 10
• StringDataset.readFixedLength() fixes by @jonaswitt

Swift 3.0

• Update to Swift 3.0
• Add support for attributes

Update to HDF5 1.10.0

Update the distribution code to the latest version of the HDF5 library.

Safe UnsafePointers

Fix a few issues related to using UnsafePointer to interface with the C library.

Chunked Datasets

• Add support for chunked datasets
• Add hyper slab selection
• Improve Dataset reading and writing convenience